code: def get_scheduler(self) -> LearningRateScheduler:
      return LearningRateScheduler.from_params(
          Params(
              {
                  "type": "combined",
                  "schedulers": [
                      [
                          2,
                          {
                              "type": "polynomial_decay",
                              "warmup_steps": 10,
                              "end_learning_rate": 0.5,
                          },
                      ],
                      [
                          5,
                          {
                              "type": "polynomial_decay",
                              "warmup_steps": 0,
                              "end_learning_rate": 0.1,
                          },
                      ],
                  ],
              }
          ),
          optimizer=self.optimizer,
          num_steps_per_epoch=10,
      )
  
file_path: allennlp/tests/training/learning_rate_schedulers/combined_test.py
imports: import torch
  from allennlp.common.testing import AllenNlpTestCase
  from allennlp.common.params import Params
  from allennlp.training.learning_rate_schedulers import LearningRateScheduler, CombinedLearningRateScheduler, PolynomialDecay
  from allennlp.training.optimizers import Optimizer
label_desc: Use image node_id 2 for calling the TestCombinedLRScheduler obj's underlying member method code with example usage: obj.get_scheduler() and returns: LearningRateScheduler